JP5964026B2 - Reinforced slab structure and its construction method - Google Patents

Description

  The present invention relates to a reinforced slab structure and a construction method thereof, and more particularly, an RC structure or an SRC structure, and an independent reinforcement frame or brace is provided outside an existing building having a ramen structure or a wall-type ramen structure. The present invention relates to a reinforcing slab structure for constructing a frame and connecting it to an existing building to increase horizontal strength during an earthquake and the construction method.

  As a method of joining the RC structure or SRC structure from the outside of the building, the required number of holes can be drilled after roughening the entire surface of the existing structure by chipping. After dawn, the most common method is to fix the post-installed anchor with an adhesive, construct a new RC slab on site, and connect the existing beam to the reinforcing frame beam.

  Conventionally, various techniques relating to a horizontal force transmission member that structurally integrates an existing building and a reinforcing frame have been proposed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  In the seismic reinforcement method for an existing building described in Patent Document 1, a plurality of gate-shaped or V-shaped horizontal force transmission members made of a flat metal material are arranged along the beam axis direction of the reinforcing column beam frame, One end is fixed to the lower surface of the spring slab of the existing building with an anchor member, and the other end of the horizontal force transmission member is fixed to the reinforcing column beam frame.

  The seismic reinforcement structure for an existing building described in Patent Document 2 is a method for seismic reinforcement of an existing building in which a separately constructed reinforcing column beam frame is tightly coupled to the outside of an existing building having a protruding slab having a rising portion at the tip. It is about. In this seismic reinforcement method for an existing building, the reinforcing column beam frame is constructed by arranging each column and beam in an arrangement corresponding to each column and beam on the outer periphery of the existing building, and the beam of the reinforcing column beam frame is Ties with the slab of an existing building. Then, the rising portion of the protruding slab is removed, and a rising portion is newly provided in the frame surface of the reinforcing column beam frame.

  The earthquake-proof reinforcement structure that also serves as a modification of the existing veranda described in Patent Document 3 is constructed with a foundation on the outside of the veranda of the existing building, and a precast pillar and a beam with a precast veranda support on the foundation. To build an integrated outer frame. Furthermore, the veranda support part integrated with the beam is arranged below the existing veranda, the veranda support part and the existing veranda are integrated, and the existing veranda is repaired and reconstructed. Then, the outer frame can bear the seismic force acting on the existing building via the veranda support section.

JP 2009-209658 A JP 2009-209585 A JP 2003-206636 A

  By the way, there are many cases where existing cantilever slabs such as shared external corridors and balconies are attached to the beams of the reinforcing surface located outside the existing building. In particular, the common corridor is the only way to reach the room from a daily staircase or elevator. In addition, both the balcony and the common corridor are often planned as condemned passages during disasters. Therefore, even if it is a short-term reinforcement work, the function as a passage must be maintained.

  However, when the formwork assembly and the rebar assembly are performed at the reinforcement construction site, the function as the passage is remarkably deteriorated, and sometimes a closing measure is required. In addition, when the span of the connecting slab becomes large, even if a wooden formwork or deck plate is used, a support work (support) will be placed in the center of the span during the period from concrete placement to strength development. Such a support work becomes an obstacle at the center of the passage as it is, and there is a problem that the passage function is significantly inhibited.

  As a measure to solve such problems, a general designer can easily think of making the lower half of the RC slab at the factory, that is, omitting the support work using the half PC floor board. It is. However, the half PC floor board is heavy and cannot be handled manually. In other words, it is impossible to suspend a half PC floor board directly under this existing slab with the existing cantilever slab left directly above the floor where the reinforcement work is to be performed, except by using heavy machinery. Most cases are difficult to implement.

  In addition, when reinforcing bars and formwork are assembled at a reinforcement construction site, not only the work days are lengthened, but also various materials and tools are scattered in the work place, which further impedes the function as a passage.

  In addition, some of the conventional techniques described in each of the above-mentioned patent documents can perform the construction without entering a dedicated part of the building during the construction period. It was hard to say that it was solved.

  The present invention has been proposed in view of the above-mentioned circumstances, and when reinforcing an existing building, it is easy to construct without obstructing the passage of a shared external corridor or balcony existing outside the existing building. An object of the present invention is to provide a reinforced slab structure that can be further shortened and a construction method thereof.

The reinforcing slab structure and the construction method thereof according to the present invention have the following features in order to achieve the above-described object. That is, the reinforced slab structure and its construction method of the present invention relates to a reinforced slab structure using a cantilever slab that connects between an existing frame and an externally reinforced frame and its method of construction.

The reinforcing slab structure of the present invention is installed under the cantilevered slab, extends in the length direction of the cantilevered slab, and has a hollow shape for increasing the moment of inertia of the section per weight compared to the solid section. A formwork member made of a cement-based extruded plate having a plurality of hollow parts, a slab rebar disposed between the formwork member and the cantilevered slab, and a concrete that is driven between the cantilevered slab and the formwork member And a fixing portion to the concrete formed by bending the outer end of the reinforcing bar inserted in the concrete so as to protrude from both ends of the hollow portion at an appropriate position provided on the mold member. It is a feature.

  Further, in addition to the above-described configuration, in the slab reinforcing bar, the strength reinforcing bars are assembled into subdivisions with the length required for the lap joints, approximately the width of the formwork member, and the main reinforcing bars are It is preferable that the construction anchor and the lap joint are provided on the existing frame and the adjacent distribution bars are the lap joint.

Further, in addition to the above-described configuration, it is preferable to provide crack reinforcing reinforcing bars that are provided in the mold member and inserted in series in a hollow portion at an appropriate position where the reinforcing bars are not inserted and are not restrained by the mold member. .

The method for constructing a reinforced slab structure of the present invention has a plurality of hollow portions that extend in the length direction of the cantilevered slab and have a hollow shape for increasing the moment of inertia of the cross section per weight as compared with the solid cross section. Using a cement-based extruded plate as a formwork member, inserting a reinforcing bar so that it protrudes from both ends of the hollow part at an appropriate position, and bending the outer end of the reinforcing bar to form a fixing part to concrete In a hollow portion at an appropriate position where no reinforcing bar is inserted , a crack reinforcing reinforcing bar is inserted in a series without being constrained by the mold member, and a pre-assembled slab reinforcing bar is disposed on the upper part of the mold member. Forming a reinforced slab structure by installing a formwork member with slab rebars placed under the cantilevered slab and driving concrete between the cantilevered slab and the formwork member so That.

According to the reinforcing slab structure and the construction method of the present invention, the weight per unit area of the formwork member is light, so that heavy machinery such as a crane is used while leaving the existing cantilever slab (common hallway, balcony). It becomes possible to construct without. For example, a half PC floor board with a thickness of 8 cm has a weight of about 200 kg / m ² , whereas an extruded board with a thickness of 26 mm has a very light weight of 30 kg / m ^2. Has been. Moreover, since the formwork member is lightweight, if it is a span of about 2 m, a support work is not required in the center, and the passage is not obstructed.

  Moreover, since the extrusion-molded board used as a formwork member has a beautiful appearance, it can be used as it is without finishing work. In addition, since the extrusion-molded plate used as the mold member is a cement-based material, it is a fire-resistant material, and no special fire-proof measures are required.

  In addition, the slab rebar is pre-assembled at another location in advance, and the construction period at the site can be shortened by setting the pre-assembled rebar on the extruded plate mold that will be the mold member. Is possible.

  Furthermore, the reinforcing bars inserted into the hollow part of the extrusion-molded plate serving as the mold member and the crack reinforcing reinforcing bars inserted in series into the other hollow part bear the weight of the entire mold member. Therefore, even if loss of adhesive strength with concrete, crack damage in the middle of the span, etc. occur, the formwork member is firmly fixed to the slab reinforcement structure by the reinforcing bars inserted in the hollow part, and the hollow part Since the extrusion-molded plate is reinforced by the crack reinforcing reinforcing bars inserted in series, it is possible to prevent the mold member from falling.

The cross-sectional schematic diagram of the reinforcement slab structure which concerns on embodiment of this invention. The partial perspective view and sectional drawing of a formwork member. Sectional drawing of the formwork member of the state which inserted the reinforcing bar in the hollow part. The perspective view and sectional drawing of the state which inserted the reinforcing bar and the crack reinforcement reinforcing bar in the hollow part.

  Hereinafter, embodiments of a reinforcing slab structure and a construction method thereof according to the present invention will be described with reference to the drawings. 1 to 3 show a reinforcing slab structure according to an embodiment of the present invention. FIG. 1 is a schematic sectional view of the reinforcing slab structure, and FIG. 2 is a partial perspective view (a) and a sectional view of a formwork member. (B), FIG. 3 is a cross-sectional view of the formwork member in a state where the reinforcing bar is inserted into the hollow part, and FIG. 4 is a perspective view (a) and a cross-sectional view (b) of the state where the reinforcing bar and the cracked reinforcing bar are inserted into the hollow part. It is.

<Outline of reinforced slab structure>
The reinforcement slab structure and its construction method according to the embodiment of the present invention use an extruded plate made of a cement-based material as a formwork member capable of holding a load during construction. The formwork member is not expected to function as a joint structure. In addition, the cross-sectional shape of the formwork member made of extruded plate is devised so that the secondary moment per weight is larger than the solid cross-section by providing a cavity near the neutral axis, and depending on the load during construction The one that works effectively against bending stress is used. Commercial products exist as such extrusion-molded plates.

  In addition, the slab reinforcing bars are assembled in advance elsewhere and placed on an extruded plate used as a formwork member, and the slab reinforcing bars and the formwork are set simultaneously. At this time, the distribution bars of the slab reinforcing bars are assembled in a subdivision with a length obtained by adding the length necessary for the lap joint to the width of the extruded plate. Moreover, the main reinforcement of a slab reinforcement is used as a construction joint and a lap joint after it is provided in an existing frame, and the distribution bars of adjacent slab reinforcements are also used as a lap joint. Moreover, a reinforcing bar is inserted in the hollow part (hollow part) of an extrusion-molded board, and the outer both ends of this reinforcing bar are bent and fixed in slab concrete. Furthermore, it is preferable to insert the cracked reinforcing bars in series into the other hollow part (cavity part) of the extruded plate.

<Formwork member>
As shown in FIGS. 1 and 2, the mold member 30 is provided under a cantilever slab 20 (for example, a common hallway or balcony) provided on the outer wall surface of the existing frame 10 including the existing beam 11 and the existing pillar 12. It consists of the cement-type extrusion board which is installed in the side and has the some hollow part 31 extended in the length direction of the cantilever slab 20. As shown in FIG. As the mold member 30, for example, a cement-based extruded plate having a weight of 29.5 kg / m ² , a thickness of 26 mm, and a standard width of 600 mm is used. A commercially available product can be used as such a cement-based extruded plate.

  Further, as shown in FIG. 3, reinforcing bars 80 are inserted from both ends of appropriate hollow portions 31 provided in the mold member 30, the outer end portions thereof are bent upward by 90 degrees, and further, the mold member 30. The concrete fixing portion 81 is formed by bending 90 degrees toward the inside. The reinforcing bar 80 is a member that functions as a drop preventing reinforcing bar of the mold member 30 together with the crack preventing reinforcing bar 100. Specifically, as shown in FIG. 4, for example, the above-described reinforcing bars 80 are inserted into two hollow portions 31 provided in the mold member 30. Further, the crack reinforcing steel bars 100 are inserted in series into the hollow part 31 located at the approximate center of the two hollow parts 31 into which the reinforcing bars 80 are inserted.

  In addition, the reinforcing bar 80 and the crack reinforcing steel bar 100 are not limited to so-called reinforcing bars, and may be any members as long as they are rod-shaped metals. Moreover, in the example shown in FIG.3 and FIG.4, in order to improve workability and to reduce cost, the reinforcing bar 80 is divided into two parts and inserted from both side openings of the hollow part 31, respectively. It is also possible to insert a series of reinforcing bars and form fixing portions 81 at both ends of the reinforcing bars. When the reinforcing bars 80 are a series, the cracked reinforcing bars 100 can be omitted. Moreover, the number of the reinforcing bars 30 to be inserted and the number of cracked reinforcing bars 100 to be inserted can be appropriately changed and set according to the construction object.

  Extruded plates look good enough to be used on outer wall panels, and you want to keep them as drive-in molds, but you can't allow them to drop. Therefore, by using the reinforcing bar 80 and the crack reinforcing steel bar 100 for preventing the formwork member 30 from falling, it will be bonded to the concrete 70 (concrete 70 to be driven between the formwork member 30 and the cantilevered slab 20 in the future). Even if the force is lost or cracking damage occurs in the middle of the span, the mold member 30 does not fall.

<Slab rebar>
The pre-assembled slab reinforcing bar 50 is disposed between the formwork member 30 and the cantilevered slab 20 and assembled in advance, and the main reinforcing bar 51 of the slab reinforcing bar 50 is provided on the existing frame 10. The construction anchor 40 and the lap joint are used, and the power distribution bars 52 of the adjacent slab reinforcing bars 50 are used as the lap joint.

  That is, the main bar 51 and the distribution bar 52 of the slab reinforcing bar 50 are pre-assembled to about 1000 mm, which is the width of the mold member 30 plus the length necessary for the lap joint, and the mold member 30 of the slab reinforcing bar 50 at the construction site. It is set on the spacer 90 above. In addition, since the main reinforcement 51 and the distribution bar 52 of the slab reinforcing bar 50 can be constructed only by the lap joint, the joint work on site is unnecessary.

<Post-cast concrete>
Then, a concrete slab structure is constructed by driving the concrete 70 between the formwork member 30 and the existing cantilever slab 20, and the existing frame 10 and the external reinforcement frame are connected.

<Reinforcement slab construction method>
In order to construct the reinforced slab structure of the present embodiment, first, the post-construction anchor 40 is attached to the outer wall surface of the existing frame 10 below the existing cantilever slab 20 to which the formwork member 30 is attached. Further, the temporary receiving angle 60 is attached to the outer wall surface of the existing frame 10 and the inner surface side (existing frame 10 side) of the reinforcing frame (not shown).

  Then, the slab reinforcing bars 50 that are assembled in advance in the width of the mold member 30 are arranged on the mold member 30 through the spacers 90. Further, the reinforcing bar 80 is inserted into an appropriate hollow portion 31 provided in the mold member 30, the outer end portion of the reinforcing bar 80 is bent upward, and the distal end portion is directed toward the inner side of the mold member 30. A 180 degree hook (fixing portion 81) is formed by bending. In the present embodiment, two reinforcing bars 80 are inserted into the hollow portion 31 of the formwork member 30 from both openings of the hollow portion 31, respectively. Further, the crack reinforcing steel bars 100 are inserted in series into other appropriate hollow portions 31 provided in the mold member 30. At this time, the reinforcing bars 80 in an amount capable of bearing the weight of the formwork member 30 may be arranged uniformly.

  Then, concrete 70 is driven between the formwork member 30 and the existing cantilever slab 20 to construct a reinforced slab structure, and the existing frame 10 and the external reinforcement frame are connected.

  As described above, in the reinforced slab structure and the construction method thereof according to the present invention, by using a light weight extruded plate as the mold frame member 30, only the temporary frame 60 attached to the existing frame 10 and the reinforcement frame is used. Since the weight of the member 30 can be borne, it is not necessary to provide support such as a support in the center of the span. As a result, the reinforcing slab structure can be easily constructed without impeding the passage of a common external corridor or balcony existing outside the existing building, and the construction period can be further shortened.

DESCRIPTION OF SYMBOLS 10 Existing frame 11 Existing beam 12 Existing column 20 Cantilever slab 30 Formwork member 31 Hollow part 40 Post-construction anchor 50 Slab reinforcement 51 Main reinforcement 52 Load reinforcement 60 Temporary receiving angle 70 Concrete 80 Reinforcement (or bar metal)
81 Fixing portion 90 Spacer 100 Cracked reinforcing bar (or bar-shaped metal)

Claims (4)

A reinforced slab structure using a cantilever slab that connects between an existing frame and an external reinforcement frame,
A plurality of hollow portions that are installed under the cantilevered slab, extend in the length direction of the cantilevered slab, and have a hollow shape for increasing a cross-sectional secondary moment per weight as compared to a solid cross-section. A mold member made of a cement-based extruded plate,
A slab rebar disposed between the formwork member and the cantilevered slab;
Concrete to be driven between the cantilever slab and the formwork member;
A fixing portion to concrete formed by bending the outer end of a reinforcing bar inserted into the concrete in a state of projecting from both ends of a hollow portion at an appropriate position provided in the mold member;
Reinforced slab structure characterized by comprising   In the slab reinforcing bar, the distribution bar is assembled in a subdivision with the length required for the lap joint to the width of the formwork member, and the main reinforcing bar is provided in the existing frame. The reinforcing slab structure according to claim 1, wherein the post-construction anchor and the lap joint are used, and adjacent force distribution bars are lap joints. Provided in the hollow part of the appropriate position where the rebar is not inserted, provided with the crack member reinforcing cracks inserted in series in a state not restrained by the formwork member ,
The reinforced slab structure according to claim 1 or 2 , characterized in that A method of constructing a reinforced slab structure for increasing horizontal strength using a cantilever slab connecting between an existing frame and an external reinforcement frame,
A cement-based extruded plate having a plurality of hollow portions extending in the length direction of the cantilevered slab and having a hollow shape for increasing the moment of inertia of the cross section per weight as compared to a solid cross section is used as a mold member. Use
Insert a reinforcing bar so that it protrudes from both ends of the hollow part at an appropriate position, bend the outer end of the reinforcing bar to form a fixing part to concrete, and an appropriate position where the reinforcing bar is not inserted In the hollow part of the above, a series of cracked reinforcing bars are inserted without being restrained by the formwork member ,
A pre-assembled slab rebar is placed on top of the formwork member;
On the lower side of the cantilever slab, the mold member in which the slab rebar is disposed is installed,
Concrete is driven between the cantilever slab and the formwork member,
A method of constructing a reinforced slab structure characterized by that.

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